The invention relates to mechanical elements that are used by external fixators and methods to manufacture such mechanical elements.
External fixators are well known by prior art, for example from U.S. Pat. No. 5,891,144, the disclosure of which is incorporated herein by reference. Such external fixators are used for stabilizing two parts of a fractured bone and holding the parts of the bone in the correct position during the healing process. Typically external fixators comprise several pins for bony attachment, rods or bars for holding the position of the pins and clamping means for connecting the pins with the rods. These external fixator elements are usually made of stainless steel, titanium or aluminum.
U.S. Publication No. 2006/0039750, the disclosure of which is incorporated herein by reference, shows a polymeric clamp.
Weight considerations, especially for long term patients wearing an external fixator for extended periods of time, request a further change of material towards plastic or polymeric based materials, as well as the request to have X-ray transparency of the device. However, it is a drawback of external fixator elements of such prior art, especially when rods are made of such light weight materials, that rods may change the position relative to the clamp and therefore to other rods and pins over time due to frictional problems.